Method and apparatus for forming varied strength zones of a vehicle component

ABSTRACT

A die apparatus including a first die element, a plurality of second die elements, a plurality of actuators, and a controller is provided. Each of the plurality of actuators is mounted to one of the plurality of second die elements. The controller is programmed to activate the actuators to contact and compress portions of a blank disposed between the die elements at separate pressures to influence microstructure forming for one of a geometry transition region, a deformation region, and a joining region. One of the separate pressures applied to one of the portions of the blank may be approximately 5 N/mm 2  or less to form a soft strength zone. The pressure of approximately 5 N/mm 2  or less may be applied to the one of the portions of the blank for approximately one to two seconds.

TECHNICAL FIELD

This disclosure relates to a method and apparatus for forming variedstrength zones of a vehicle component.

BACKGROUND

Automotive manufacturers are driven to design light weight vehicles withincreased crash performance and reduced fuel consumption. Themanufacturers have transitioned from a usage of mild steels for vehiclecomponents to advanced high strength steels and ultra-high strengthsteels along with aluminum. Hot stamping processes for vehiclecomponents allow creation of fully martensitic structures. However, thehot stamping process may create vehicle components with undesirablequalities. Further, many process variables exist due to a complexity ofthe hot stamping process.

This disclosure is directed to solving the above problems and otherproblems as summarized below.

SUMMARY

A die apparatus includes a first die element, a plurality of second dieelements, a plurality of actuators, and a controller. Each of theplurality of actuators is mounted to one of the plurality of second dieelements. The controller is programmed to activate the actuators tocontact and compress portions of a blank disposed between the dieelements at separate pressures to influence microstructure forming forone of a geometry transition region, a deformation region, and a joiningregion. One of the separate pressures applied to one of the portions ofthe blank may be approximately 5 N/mm² or less to form a soft strengthzone. The pressure of approximately 5 N/mm² or less may be applied tothe one of the portions of the blank for approximately one to twoseconds. One of the separate pressures applied to one of the portions ofthe blank may be approximately 20 N/mm² or more to form a hard strengthzone. The approximately 20 N/mm² or more may be applied to the one ofthe portions of the blank for a time period based on a thickness of theblank to form a fully martensitic microstructure. The first die elementmay include a coolant channel having a first portion spacedapproximately 20 mm or more from one of the portions of the blank and asecond portion spaced approximately 8 mm or less from another of theportions of the blank. The first die element and the plurality of seconddie elements may be of a material having low thermal conductivity atfirst die element locations adjacent a desired soft strength zone of theblank and of a material having high thermal conductivity at second dieelement locations adjacent a desired hard strength zone of the blank.The material having a low thermal conductivity may be a ceramic materialand the material having high thermal conductivity may be AISI hot worktool steel H13.

A method for forming a targeted soft strength zone for a vehiclecomponent includes activating one or more of a plurality of actuatorseach mounted to one of a plurality of lower die elements to separatelycompress a desired soft strength zone of a blank for a predeterminedtime period against an upper die element at a first pressure sufficientto form the blank into a vehicle component. The method further includesreleasing the compression of the one of the plurality of actuators andretaining the vehicle component between the plurality of lower dieelements and the upper die element without contacting the die elementsto prevent martensitic transformation of the desired soft strength zoneof the blank. The method may further include activating another of theone or more of the plurality of actuators to separately compress theblank against the upper die element at a second pressure to influencemartensitic transformation of a desired hard strength zone of the blank.The second pressure may be approximately 20 N/mm² or more. The methodmay further include aligning the soft strength zone with a first portionof a coolant channel spaced a first distance from the blank; andaligning the hard strength zone with a second portion of the coolantchannel spaced a distance less than the first distance from the blank.The first pressure applied may be approximately 5 N/mm² or less. Thepredetermined time period may be approximately one to two seconds.

A method for forming a vehicle component having varied strength zonesincludes positioning a blank between a first die element and a pluralityof second die elements each mounted to an actuator so that a desiredsoft strength zone is spaced from a first portion of a coolant channelof the first die element at a first distance and a desired hard strengthzone is spaced from a second portion of the coolant channel at a seconddistance. The method further includes activating the actuators tocompress the blank at a first pressure against the first die element toform the vehicle component. The method further includes activating oneor more of the actuators to compress the hard strength zone of the blankat a second pressure against the first die element. The method furtherincludes releasing the compression and retaining the now formed vehiclecomponent between the die elements such that coolant within the coolantchannel does not influence a martensitic transformation of the softstrength zone and does influence a martensitic transformation of thehard strength zone. The first pressure may be approximately 5 N/mm² orless. The second pressure may be approximately 20 N/mm² or more. Themethod may further include retaining the formed vehicle componentbetween the die elements so that the soft strength zone of the vehiclecomponent does not contact either of the die elements. The firstdistance may be between approximately eight millimeters and twentymillimeters. The second distance may be approximately eight millimetersor less.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an example of a die apparatus.

FIG. 2 is a block diagram of an example of a vehicle component formingsystem.

FIG. 3 is a flow chart of an example of a method to form a vehiclecomponent.

FIG. 4 is a side view of an example of a front rail of an underbodyassembly.

FIG. 5 is a perspective view of an example of a bumper beam assembly.

FIG. 6 is a side view of an example of a rear rail of an underbodyassembly.

FIG. 7 is a perspective view of a fuel tank protection assembly.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described herein. It is to beunderstood, however, that the disclosed embodiments are merely examplesand other embodiments can take various and alternative forms. Thefigures are not necessarily to scale; some features could be exaggeratedor minimized to show details of particular components. Therefore,specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a representative basis forteaching one skilled in the art to variously employ the presentdisclosure. As those of ordinary skill in the art will understand,various features illustrated and described with reference to any one ofthe figures can be combined with features illustrated in one or moreother figures to produce embodiments that are not explicitly illustratedor described. The combinations of features illustrated providerepresentative embodiments for typical applications. Variouscombinations and modifications of the features consistent with theteachings of this disclosure, however, could be used in particularapplications or implementations.

FIG. 1 illustrates a schematic example of a die apparatus, referred toas a die apparatus 10 herein. The die apparatus 10 includes variouscomponents including a first die element and a plurality of second dieelements. For example, the die apparatus 10 may include an upper dieelement 14 and a plurality of lower die elements. The plurality of lowerdie elements may include a first lower die element 16, a second lowerdie element 18, and a third lower die element 20. The upper die element14 may vertically translate as represented by arrows 19 or may bestationary. Each of the plurality of lower die elements may verticallytranslate as represented by arrows 21. In another example, orientationsof the upper die element 14 and the plurality of lower die elements maybe swapped with one another so that the upper die element 14 is locatedbelow the plurality of lower die elements. The upper die element 14 andthe plurality of lower die elements may be arranged with one another sothat a blank 22 may be positioned therebetween. A fixture 23 may retainthe blank 22 in position between the die elements. The upper die element14 and the plurality of lower die elements may use a differentialcooling process and/or pressure applications to form a vehicle componentfrom the blank 22 having desired and varied strength zones along thevehicle component.

The upper die element 14 includes a coolant channel for coolant to flowtherethrough. For example, the upper die element 14 may have a coolantchannel 26. Other examples of coolant channels are available based on adesired spacing between the blank 22 and the respective coolant channel.Varied spacing between the coolant channel and the blank 22 assists informing varied strength zones along the blank 22 when coolant flowsthrough the coolant channel 26.

A first length 29 between the blank 22 and the coolant channel 26 ofapproximately twenty millimeters or more assists in forming a softstrength zone 31 of the blank 22 when coolant flows through the coolantchannel 26. The soft strength zone 31 may be located at a joininglocation for the blank 22 or the vehicle component and may include amicrostructure having one or both of pearlite and ferrite and has atensile strength of 400 to 600 MPa. Generally, the soft strength zonewill have low thermal conductivity characteristics (less than 10 W/m-k)and a low surface absorptivity characteristic with a reflective coating.Ceramic is one example of a material having low thermal conductivity.While in this example the soft strength zone 31 is located at a joininglocation, it is contemplated that the soft strength zone 31 may belocated at various types of vehicle component zones in which theassociated microstructure of the soft strength zone 31 is desired.Another example of a location for the soft strength zone includes alocation on a vehicle component adjacent a harder strength zone in whichthe soft strength zone is arranged to absorb energy from an impact priorto the energy reaching the harder strength zone.

A second length 35 between the blank 22 and the coolant channel 26 ofapproximately eight millimeters or less assists in forming a hardstrength zone 37 of the blank 22 when coolant flows through the coolantchannel. The hard strength zone has a fully martensitic microstructureand a tensile strength of 1000 to 1900 MPa. Generally, the hard strengthzone will have high thermal conductivity characteristics (greater than25 W/m-k) and a high surface absorptivity characteristic. AISI hot worktool steel H13 is one example of a material having high thermalconductivity.

The die apparatus 10 may also use pressure applications to form thevarious strength zones of a vehicle component. As mentioned above, eachof the plurality of lower die elements may operate to retain one or moreportions of the blank 22 at the desired spacing from the coolant channel26 of the upper die element 14. Each of the lower die elements may alsoapply a pressure to the blank 22 at different portions of the blank 22to form varied microstructures. For example, the first lower die element16 may be mounted to a first actuator 40, the second lower die element18 may be mounted to a second actuator 42, and the third lower dieelement 20 may be mounted to a third actuator 44. In one example, eachof the actuators is an air driven cylinder. A controller (shown in FIG.2) may be in communication with the actuators and a coolant distributor(shown in FIG. 2) to direct operation of the die apparatus 10.

FIG. 2 is a block diagram illustrating an example of a system forforming varied strength zones of a vehicle component. The systemincludes a die apparatus, such as the die apparatus 10, and a controller50. The controller 50 is in communication with the first actuator 40,the second actuator 42, the third actuator 44, and a coolant distributor54 to direct operation thereof. The controller 50 may direct each of theactuators to operate at a separate pressure and to direct the coolantdistributor 54 to deliver coolant to a coolant channel, such as thecoolant channel 26. For example, separate pressure commands from thecontroller 50 direct each of the actuators to contact and apply apressure to different portions of the blank 22 positioned between theupper die element 14 and the plurality of lower die elements.

To form a hard strength zone, application of a pressure by one of theactuators in an amount of approximately 20 N/mm² or more is applied tothe blank 22. The formed vehicle component may then be held in positionuntil a target temperature of 170 degrees Celsius is reached for thedesired hard strength zone. For example, if the formed vehicle componenthas a thickness of 1.4 millimeters, the formed vehicle component may beheld in position for five to six seconds to form the hard strength zone.

To form a soft strength zone, application of a pressure by one of theactuators in an amount of approximately 5 N/mm² or less is applied tothe blank 22. The pressure is held for approximately one to two secondsbased on a thickness of the blank 22. After the approximately one to twoseconds, the pressure of the actuator is released and the now formedvehicle component is oriented so that minimal or no contact existsbetween a die surface and the vehicle component. The vehicle componentis then held in position until the hard strength zones are formed indesired locations at the approximately 170 degrees Celsius while atemperature of the desired soft strength zones stays above temperaturesdriving martensitic formation. The vehicle component may then be removedand stored in a holding cell for air cooling.

FIG. 3 is a flow chart showing an example of a method to form a vehiclecomponent having varied strength zones, referred to as a method 100. Themethod 100 may use a die, such as the die apparatus 10, and acontroller, such as the controller 50, to form a vehicle componenthaving varied strength zones.

In operation 104, a vehicle component design requirement is identified.For example, a portion of a vehicle component may be identified as ajoining location comprising an area for securing to another component. Asofter strength zone may be preferred for the joining location due tosubsequent assembly processes having less difficulty in securing thesoft strength zone to another vehicle component in comparison to joiningharder strength zones of vehicle components to one another. In anotherexample, deformation characteristics may be identified as a vehiclecomponent design requirement. These deformation characteristics may bebased on microstructures of various portions of the vehicle component.The deformation characteristics may include a portion of a vehiclecomponent having a softer strength zone to deform when a load isreceived to absorb energy from the load prior to reaching adjacentportions of the vehicle component. Non-limiting examples of vehiclecomponents include an underbody assembly rear rail, an underbodyassembly front rail, a bumper beam, and cross members of a fuel tankprotection assembly.

In operation 106, a type of material for a blank may be selected.Different types of blank materials have different characteristics whichmay or may not be desirable for particular thermal treatmentapplications. Examples of materials for blanks include Aperam HotForming Grades, Ductibor (HF 340/480), Usibor 1500 (HF 1050/1500),Usibor 1900 (HF 1200/1900), US Steel 10B20, Boron, 20MNB5, 22MNB5,8MNCrB3, 27MnCrB5, and 37MnB4.

The selected blank material may be coated or uncoated. Determination ofwhether the blank includes a coating and a type of coating may bedetected by a sensor. The coating may assist in minimizing or preventingoxidation of a surface of the blank under certain thermal conditionssuch as a heat treatment of 250 degrees Celsius or higher. The coatingmay also provide corrosion resistance benefits for vehicle componentswhich may be later subjected to environment conditions. Examples ofsubstances for the coating include zinc, aluminum-silicon, andzinc-nickel. Uncoated blanks may be used to reduce production costs orfor vehicle components that do not need to be designed for surfacecorrosion prevention.

In operation 108, a treatment schedule is identified to treat targetedzones of the blank based on the previously defined design requirement toform predetermined microstructures or strength zones of the vehiclecomponent. The treatment schedule may include a use of coolant within acoolant channel to influence austenitization and pressure applicationsto influence desired microstructure formation.

In operation 110, the blank is arranged with the die apparatus betweenan upper die element and a plurality of lower die elements based on theidentified design requirement to form the predetermined microstructures.In operation 112, the treatment schedule may be applied to the blank andthe vehicle component may be formed from the blank. For example, to forma soft strength zone, the upper and lower die elements may be closed andan amount of pressure of approximately 5 N/mm² or less between isapplied to the blank by actuators mounted to the lower die elements forone to two seconds to form a desired component geometry and desiredmicrostructure.

To form a hard strength zone, the upper and lower die elements may beclosed and an amount of pressure of approximately 20 N/mm² or more isapplied to the blank by actuators mounted to the lower die elements foran amount of time based on a thickness of the blank. For example, thepressure of approximately 20 N/mm² or more may be applied for 5 to 6seconds for a blank having a thickness of 1.4 mm to form the hardstrength zone.

FIG. 4 through 7 illustrate examples of vehicle components which may becreated with the method 100 described above. FIG. 4 illustrates anexample of a front rail 170 for a vehicle underbody assembly which maybe treated by the method 100 to accommodate for a design requirementrelating to deformation characteristics at a vehicle component geometrytransition. The front rail 170 may be created by the method 100 to formvarious strength zones. For example, the front rail 170 may include afirst zone 172, a second zone 174, a third zone 176, and a fourth zone178. The third zone 176 extends between the second zone 174 and thefourth zone 178. The third zone 176 may be located at a portion of thefront rail 170 including a bend at a transition between a front portionof the front rail 170 and an upper end of a backup structure 180. Thefirst zone 172 may be treated to form a soft strength zone. The secondzone 174 and the fourth zone 178 may be treated form a hard strengthzone. The third zone 176 may be treated to form a strength zone weakerthan the hard strength zone.

Treating the second zone 174 to form a hard strength zone allows for theconsolidation of separate inner and outer reinforcement parts of engineand transmission attachment brackets into a single inner and outer part.

Treating the third zone 176 to form a softer strength zone relative tothe second zone 174 and the fourth zone 178 may create a lower strengthmaterial area for creating a “living hinge” or hinge joint to absorbenergy and minimize deformation into a rocker, a hinge pillar, and avehicle cabin when the front rail 170 or a bumper beam is subjected toan impact.

Treating the fourth zone 178 to form a hard strength zone may allowreinforcement brackets that are attached to front rail 170 parts to beconsolidated in one part. The consolidated reinforcement brackets may beof AHSS material having strength to support a geometry change at alocation in which a front portion of the front rail 170 transitions tothe backup structure 180 to balance an offset in load direction. Thefront rail 170 may transition from a substantially straight portionextending rearward and then downward and outboard to meet a vehiclepillar or rocker. A rear portion of the front rail 170 may be subject toa large bending moment due to the geometry change (downward andoutboard). In prior art examples, the portion of the rail with ageometry change is typically reinforced with brackets to controldeformation. In this example, the backup structure 180 extendslongitudinally and outboard relative to a vehicle body. The front rail170 has a reduced number of components and joints compared to prior artfront rails so fewer joining operations are required for assembly.

FIG. 5 illustrates an example of a bumper assembly 184 for a vehiclewhich may be treated to accommodate various desired strength zones for adesign requirement relating to joining characteristics. For example, thebumper assembly 184 includes a bumper beam 186 having a first end 188, asecond end 190, and a middle portion 192 extending between the first end188 and the second end 190. The first end 188 extends inboard andoutboard of one of a pair of crush cans 196. The second end 190 extendsinboard and outboard of the other of the crush cans 196.

The first end 188 and the second end 190 may be treated to define softstrength zones. The middle portion 192 may be treated to form a hardstrength zone having a tensile strength between 1000 MPa and 1900 MPa.The zone identifiers may be defined by a microstructure made availableon a vehicle component due to the treatment as described in method 100above. Treating the first end 188 and the second end 190 to form softstrength zones provides for placement of desired microstructures havingdesired joining characteristics to, for example, join each of the crushcans 196 to one of the first end 188 and the second end 190.

FIG. 6 illustrates an example of a rear rail 200 for a vehicle underbodyassembly which may be treated to accommodate a design requirementrelating to a geometry transition. The rear rail 200 may be created bythe method 100 to form various strength zones. The rear rail 200includes a rear portion 202, a first mid-portion 204, a secondmid-portion 206, and a forward portion 208. A crush can 210 extends fromthe rear portion 202. The rear portion 202 defines a first central axis214. The forward portion 208 and part of the second mid-portion 206define a second central axis 216. The first central axis 214 may be in afirst plane and the second central axis 216 may be in a second plane.The second mid-portion 206 extends from the first central axis 214 tothe second central axis 216 at a geometry transition region 220. In oneexample, the second mid-portion 206 may extend downward and outboard tothe forward portion 208.

The first mid-portion 204 may be treated to form a soft strength zoneand the second mid-portion 206 may be treated to form a hard strengthzone. The rear rail 200 may be treated so that the rear portion 202 andthe forward portion 208 do not receive heat or receive minimal heat, orare subjected to appropriate pressure applications, to retain or formsoft strength zones.

An arrangement of the different strength zones of the rear rail 200provides a structure in which deformation occurs nearer a point ofimpact, e.g. a soft strength zone at the rear portion 202, and thestrongest strength zone is located upon the rear rail 200 tostructurally reinforce the geometry change at the transition region 220,e.g. a hard strength zone at the second mid-portion 206.

Locating the soft strength zone at the first mid-portion 204 provides alower strength material area for creating a “living hinge” or hingejoint to absorb energy and minimize deformation into adjacent rockersand a vehicle cabin when the rear rail 200 is subjected to an impact.

Locating the hard strength zone at the second mid-portion 206 minimizesbending which may occur in the rear rail 200 due to the geometry change(downward and outboard) at the transition region 220 without a hardstrength zone under an axial load from an impact.

FIG. 7 illustrates an example of a protection assembly for a vehicleunderbody in which components may be treated by the method 100 toaccommodate for a design requirement relating to targeted deformationcharacteristics. The protection assembly includes a first cross member230, a second cross member 232, a first longitudinal member 236, asecond longitudinal member 238, and a pair of side rails 242. Each ofthe first cross member 230 and the second cross member 232 extendbetween the pair of side rails 242. Each of the pair of side rails 242is mounted to one of a pair of rockers 246. Each of the firstlongitudinal member 236 and the second longitudinal member 238 extendbetween the cross members. The protection assembly provides structuralreinforcement and protection for vehicle components when side and rearimpacts are received. For example, a vehicle component, such as a fueltank or seat assembly, may be arranged with the protection assembly toprevent or limit contact to the vehicle component by other vehiclecomponents due to a vehicle impact. Targeted treatment of the componentsof the protection assembly assists in preventing or limiting thecontact.

For example, the first cross member 230 may be treated by the method 100to form a hard strength zone at a central region 250 and soft strengthzones on either side of the central region 250 at a first end 252 and asecond end 254. The second cross member 232 may be treated by the method100 to form a hard strength zone at a central region 260 and softstrength zones on either side of the central region 260 at a first end262 and a second end 264.

Treating the ends of the first cross member 230 and the second crossmember 232 to form strength zones having a lower tensile strength thanthe respective central regions may create a lower strength material areafor creating a “living hinge” or hinge joint to absorb energy andminimize deformation. The soft strength zones of the ends of the firstcross member 230 and the second cross member 232 provide additionalcrash distance or deformation distance to minimize or prevent aside-impacted vehicle component from entering a region defined by thevehicle component. A location of soft strength zones at crush contactareas assists in facilitating sectional collapse of the first crossmember 230 and the second cross member 232 to provide additional energyabsorption before the impact load reaches the hard strength zone of therespective central region.

While various embodiments are described above, it is not intended thatthese embodiments describe all possible forms encompassed by the claims.The words used in the specification are words of description rather thanlimitation, and it is understood that various changes can be madewithout departing from the spirit and scope of the disclosure. Whilevarious embodiments could have been described as providing advantages orbeing preferred over other embodiments or prior art implementations withrespect to one or more desired characteristics, those of ordinary skillin the art recognize that one or more features or characteristics can becompromised to achieve desired overall system attributes, which dependon the specific application and implementation. These attributes caninclude, but are not limited to cost, strength, durability, life cyclecost, marketability, appearance, packaging, size, serviceability,weight, manufacturability, ease of assembly, etc. As such, embodimentsdescribed as less desirable than other embodiments or prior artimplementations with respect to one or more characteristics are notoutside the scope of the disclosure and can be desirable for particularapplications.

What is claimed is:
 1. A die apparatus comprising: a first die elementdefining an upper tool including at least one coolant channel definedtherein; a plurality of second die elements defining a lower tool, afirst set of the plurality of second die elements defining a firstpressure zone of up to 5 N/mm² between the first set and the first dieelement, and a second set of the plurality of second die elementsdefining a second pressure zone of up to 20 N/mm² between the second setand the first die element; a plurality of actuators each mounted to arespective one of the plurality of second die elements of the lowertool, the plurality of actuators corresponding to the first set and thesecond set based on respective portions of a blank disposed between theupper and lower tool via the plurality of second die elements; and acontroller programmed, as based on a treatment schedule, to activate andoperate the actuators based on separate pressure commands correspondingto the first and second set to contact and compress the portions, and todirect a coolant distributor to deliver coolant to the coolant channelto influence austenitization and pressure applications formicrostructure formation, wherein each of the first and second dieelements include respective die element locations adjacent a desiredsoft strength zone of the blank, corresponding to the first pressurezone between the first set and the first die element, the desired softstrength zone having a tensile strength of 400 to 600 MPa, andrespective die element locations adjacent a desired hard strength zoneof the blank, corresponding to the second pressure zone between thesecond set and the first die element, the desired hard strength zonehaving a tensile strength of 1000 to 1900 MPa, and wherein the dieelement locations adjacent the desired soft strength zone include amaterial having low thermal conductivity, and the die element locationsadjacent the desired hard strength zone include a material having highthermal conductivity, the low thermal conductivity being less than 10W/m-k and the high thermal conductivity being greater than 25 W/m-k. 2.The apparatus of claim 1, wherein the pressure of approximately 5 N/mm²or less is applied for approximately one to two seconds.
 3. Theapparatus of claim 1, wherein the approximately 20 N/mm² or more isapplied for a time period based on a thickness of the blank to form afully martensitic microstructure.
 4. The apparatus of claim 1, whereinthe coolant channel includes first portion spaced approximately 20 mm ormore from the desired soft strength zones, and a second portion spacedapproximately 8 mm or less from the desired hard strength zones.
 5. Theapparatus of claim 1, wherein the material having a low thermalconductivity is a ceramic material and the material having high thermalconductivity is AISI hot work tool steel H13.
 6. The die apparatus ofclaim 1, wherein the coolant channel includes a first portion positionedat a first distance from a blank contact surface corresponding to thesoft strength zone, and a second portion positioned at a second distancefrom the blank contact surface, smaller than the first, corresponding tothe hard strength zone.
 7. A die apparatus comprising: a first dieelement defining an upper tool including at least one coolant channeldefined therein; a plurality of second die elements defining a lowertool, each individual die element having either a low thermalconductivity of less than 10 W/m-k or a high thermal conductivity ofgreater than 25 W/m-k, and a first set of the plurality of second dieelements defining a first pressure zone of up to 5 N/mm² with the firstdie element, and a second set of the plurality of second die elementsdefining a second pressure zone of at least 20 N/mm² with the first dieelement; a blank positioned on the lower tool, and having at least onefirst portion corresponding to a soft strength zone of the blank andsecond die elements having the low thermal conductivity, and at leastone second portion corresponding to a hard strength zone of the blankand second die elements having the high thermal conductivity, the softstrength zone having a desired microstructure of pearlite, ferrite, orboth, and the hard strength zone having a desired microstructure ofmartensite; a first set of actuators corresponding to the first setcorresponding to the at least one first portion of the blank such thatthe at least one first portion of the blank is positioned in the firstpressure zone via the first set; a second set of actuators correspondingto the second set corresponding to the at least one second portion ofthe blank such that the at least one second portion of the blank ispositioned in the second pressure zone via the second set; and acontroller programmed, as based on a treatment schedule, to individuallyand independently activate and operate the first and second actuatorsvia separate pressure commands to contact and compress the blank basedon the at least one first portion and at least one second portion beingpositioned in a respective pressure zone on the first and second sets,and to direct a coolant distributor to deliver coolant to the coolantchannel to influence austenitization and pressure applications formicrostructure formation, wherein each of the first and second dieelements selectively correspond to the at least first or second portionsof the blank based on the soft strength zone and hard strength zone suchthat the blank has varied microstructure regions.
 8. The die apparatusof claim 7, wherein the coolant channel includes a first portionpositioned at a first distance from a blank contact surface of the uppertool corresponding to the soft strength zone, and a second portionpositioned at a second distance from the blank contact surface, smallerthan the first, corresponding to the hard strength zone.